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Monday, June 27, 2011

Today, Monday June 27 at about 17:00 UT, the asteroid designated 2011 MD will pass only 12,300 kilometers (7,600 miles) above the Earth's surface. The asteroid was discovered by Linear survey with a 1.0-m f/2.15 reflector + CCD on June 22, 2011 at magnitude 18.9.

This object is only 5-20 meters in diameter and it is in a very Earth-like orbit around the Sun. Additional observations have made it possible to exclude that this object is a piece of space junk, as was suggested early on. Calculation by Bill Gray, a well-known expert on orbital dynamics, shows that this asteroid could not have been close enough to Earth any time during the space age to have started off as a rocket booster.

Trajectory of 2011 MD from the general direction of the Sun

(credit: Nasa)

We have been able to follow-up this object few hours ago remotely from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD and from the Faulkes Telescope South through a 2.0-m f/10.0 Ritchey-Chretien + CCD.

At the moment of our images from New Mexico on June 27, 06:50UT, "2011 MD" was moving at about 132"/min and its magnitude was ~15. While the images from FTS were obtained on June 27, 09:30UT when the asteroid was moving at about 176"/min and its magnitude was ~14.5.

At the moment of its close approach later today, 2011 MD will be bright as magnitude ~11.8

Below you can see our image taken with the 0.25-m, f/3.4 reflector + CCD in New Mexico, while 2011 MD was passing nearby a bright star (click on the image for a bigger version):

Here you can see a single 20-second exposure + RGB filter image taken by 2 meters telescope at Faulkes Telescope South (click on the image for a bigger version):

While this is an animation showing the object movement in the sky. Each image was 20-second exposure with Faulkes Telescope South 2 meters telescope. Click on the thumbnail to see a bigger version:

2011 MD's Earth flyby will be a close shave, but not a record for nearby passing asteroids. The record is currently held by the asteroid 2011 CQ1, which came within 5,480 kilometers of Earth on Feb. 4 of this year. See our previous post on this object:

Saturday, June 25, 2011

IAUC nr.9218, issued on 2011, June 25, announces the discovery of a new comet (discovery magnitude 18.6) by the LINEAR survey with a 1.0-m f/2.15 reflector + CCD, on images obtained on 2011, June 22.4. The new comet has been designated C/2011 M1 (LINEAR)

After posting on the Minor Planet Center's 'NEOCP' webpage, this object has been found by several CCD astrometrists to show cometary appearance. We performed some follow-up measurements of this object while it was still listed in the NEOCP. Stacking of 15 unfiltered exposures, 60-sec each, obtained remotely on 2011, June 23.4 from the Tzec Maun Observatory (near Mayhill, NM) through a 0.35-m f/3.8 reflector + CCD, shows that this object is a comet: coma nearly 30" in diameter, with a weak central condensation. Total magnitude (unfiltered CCD) m1= 16.5 We suspect the presence of an extension, or a faint tail, nearly 40" long in PA 240, however the visibility of this detail is hampered by the moonlight.

Friday, June 24, 2011

Today we have been able to image again comet 174P/Echeclus with the 2-m Faulkes Telescope South to follow the recent bright phase of this interesting centaur.

Stacking of eight R-filtered exposures, 60-sec each, obtained remotely, from the Faulkes Telescope South on 2011, June 24.5, through a 2.0-m f/10.0 Ritchey-Chretien + CCD, shows some evolution in the morphology of this comet: the parabolic coma previously reported, albeit present, is now much fainter, and shows its ADU counts very close to the sky background limit. No other details, except a nuclear condensation having an m2 close t R about 18.9, are currently visible in our images.

Thursday, June 9, 2011

Following the recent outburst of centaur 174P/Echeclus, we performed some follow-up of this intriguing object. Stacking of 8 unfiltered exposures 300 sec each, obtained remotely, from the Tzec Maun Observatory (near Moorook, Australia) on 2011, June 8.6, through a 0.15-m, f/7.3 refractor + CCD, shows some evolution within the coma of this object: we detected the development of a (possible) faint parabolic envelope about 45-arcsec in diameter, with the central condensation having an offset of nearly 13-arcsec to the west-southwest.

Our image (click on the image for a bigger version):

Unfortunately in our image the S/N of this feature is pretty low, so further follow-up and confirming images will be very welcome.

UPDATE - June 10, 2011

Thanks to our fellow british observer Nick Howes, today we had the opportunity to image 174P/Echeclus nearly simultaneously with both the 2-m Faulkes Telescopes, under excellent seeing conditions, from Haleakala (Hawaii) and Siding Spring (Australia).

Stacking of R-filtered exposures for a total of 930 sec, obtained remotely, from the Haleakala-Faulkes Telescope North on 2011, June 10.4, through a 2.0-m f/10.0 Ritchey-Chretien + CCD under good seeing conditions, confirms the presence of a parabolic envelope, having 47-arcsec in diameter, and a broad tail (or a train of debrises) nearly 20-arcsec long and about 5-arcsecwide, toward PA 70. The nuclear condensation m2 has dropped to R about 19. Confirming observations of the above mentioned features were obtained nearly simultaneously with the Siding Spring-Faulkes Telescope South.

Below you can see our combined image of the two observing sessions, for an equivalent total exposure time of 1530 seconds, R-filtered (click on the image for a bigger version)

IAUC nr.9215, issued on 2011, June 08, announces the discovery of a new comet (discovery magnitude 19.4) on four CCD images taken with the 1.8-m "Pan-STARRS 1" telescope at Haleakala, on images obtained on 2011, June 6.4. The new comet has been designated C/2011 L4 (PANSTARRS).

After posting on the Minor Planet Center's 'NEOCP' webpage, this object has been found by several CCD astrometrists to show cometary appearance. We performed some follow-up measurements of this object while it was still listed in the NEOCP. Stacking of 14 unfiltered exposures, 180-sec each, obtained remotely on 2011, June 07.4 from the Tzec Maun Observatory (near Mayhill, NM) through a 0.35-m f/3.8 reflector + CCD, shows that this object is slightly diffused, with a hint of elongation toward the north-east.

According to this very preliminary orbit based on an arc of only 2 weeks, this comet might become a bright object ( ~ magnitude 2) around perihelion in March-April 2013 and better placed for southern hemisphere. Next weeks will tell us something more about the future of this comet!!

Monday, June 6, 2011

IAUC nr.9214, issued on 2011, June 06, announces the discovery of a new comet (discovery magnitude 16.3) by Robert H. McNaught through the 0.5-m Uppsala Schmidt + CCD at Siding Spring, on images obtained on 2011, June 3.7. The new comet has been designated C/2011 L3 (McNAUGHT).

After posting on the Minor Planet Center's 'NEOCP' webpage, this object has been found by several CCD astrometrists to show cometary appearance. We performed some follow-up measurements of this object while it was still listed in the NEOCP. Stacking of 30 unfiltered exposures, 60-sec each, obtained remotely on 2011, June 05.4 from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD, shows that this object is a comet: strong central condensation and coma nearly 25-arcsec in diameter elongated toward PA 230.

Friday, June 3, 2011

CBET circular No. 2735, issued on June 03, 2011, announces the discovery by John Seach (Australia) of a possible nova (mag 9.5) on three CCD images (limiting mag 11.0) taken on June 1.40 UT with a digital SLR camera (+ 50-mm-f.l. f/1.2 lens + orange filter).

We performed some follow-up of this object remotely with the GRAS RCOS 32-cm f/6.3 telescope at Officer, Australia. On our images taken on June 02.4, 2011 we can confirm the presence of an optical counterpart with unfiltered CCD magnitude about 9.4 (USNO-B1.0 Catalogue reference stars) at coordinates:

R.A. = 16 55 09.46, Decl.= -38 38 04.5

(equinox 2000.0; USNO-B1.0 catalogue reference stars).

Our confirmation image (click for a bigger version):

Below you can see an animation showing a comparison between our confirming image and the archive POSS2/UKSTU plate (R Filter - 1995). Click on the thumbnail below for a bigger version:

CBET circular No. 2735 also reports that A. Arai, T. Kajikawa, and M. Nagashima, Kyoto Sangyo University, performed low-dispersion optical spectroscopic observations (range 400-750 nm; R about 600) of this transient on June 2.68 UT using the 1.3-m Araki telescope (+ LOSA/F2) under a hazy sky. The spectrum shows a broad H-alpha (FWZI about 4600 km/s) with an asymmetric profile and O I (777.4 nm) on a highly-reddened continuum. No visible He or Fe II lines exist in the spectrum. These features suggest that the object is a classical nova in outburst with high interstellar reddening.

Wednesday, June 1, 2011

After reading on the [Comets-ml] forum about a possible outburst of centaur 174P/Echeclus, we performed some follow-up remotely, from the Tzec Maun Observatory (near Moorook, Australia) through a 0.15-m, f/7.3 refractor + CCD. Stacking of 7 unfiltered exposures 300 sec each, show the presence of a sharp central condensation having R magnitude about 18. We noticed also the presence of a jet-like feature nearly 6-arcsec long, emanating from the central condensation toward PA 60. A faint, spiral-like coma, having a total magnitude of about 16 and a diameter of 40-arcsec, surrounds the central condensation, resembling much comet 29P during the early phase of one of its recurrent outbursts.

Our June 01, 2011 image (click for a bigger version):

Centaurs, defined to have their perihelion outside of Jupiter (5.2 AU) and semimajor axis inside of Neptune (30.0 AU), have unstable orbits and have been extracted from the transneptunian objects (TNOs) population through perturbations by Neptune. So far only a few Centaurs have presented unambiguous evidence of cometary activity. The first Centaur known to present cometary activity was Chiron.

Echeclus was discovered by the Spacewatch program on March 3, 2000 (Marsden 2000) and initially labelled (60558) 2000 EC98. The presence of coma around (60558) 2000 EC98 was first detected by Choi and Weissman (2006) on 2005 December 30.50 UT with the Palomar 5m telescope. Soon after, the object was given the periodic comet designation 174P/Echeclus.

Below you can see some of our images dated back to 2006 when the coma was first discovered by Choi & Weissman:

IAUC nr.9210, issued on 2011, May 31, announced the discovery of a new comet (discovery magnitude 19.1) by A. Boattini through the Mt. Lemmon 1.5-m reflector + CCD, on images obtained on 2011, May 28.3 After posting on the Minor Planet Center's NEOCP webpage, this object was identified with an object reported as apparently asteroidal by the Spacewatch survey on May 8 and 12 and previously given the designation 2011 JB_15.

The new comet has been designated P/2011 JB_15 (SPACEWATCH-BOATTINI).

After posting on the Minor Planet Center's 'NEOCP' webpage, this object has been found by several CCD astrometrists to show cometary appearance. We performed some follow-up measurements of this object while it was still listed in the NEOCP. Stacking of 20 unfiltered exposures, 180-sec each, obtained remotely on 2011, May 30.3 from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD, shows that this object is a comet: coma nearly 8-arcsec in diameter with a very weak central condensation.

IAUC nr.9211, issued on 2011, May 31, announced the discovery of a new comet (discovery magnitude 19.5) by Paulo R. Holvorcem and Michael Schwartz through the Tenagra III 0.41-m astrograph + CCD, on images obtained on 2011, May 26.3 The new comet has been designated C/2011 K1 (SCHWARTZ-HOLVORCEM).

After posting on the Minor Planet Center's 'NEOCP' webpage, this object has been found by several CCD astrometrists to show cometary appearance. We performed some follow-up measurements of this object while it was still listed in the NEOCP, on 2011 May 30.4 remotely from the Tzec Maun Observatory.

Comets & Asteroids news

Welcome to our Astronomy blog, devoted in particular to Comets & Asteroids and related topics. This blog is maintained by Italian amateur astronomer Ernesto Guido, particularly active in the study of the small bodies of the Solar System.